Electrophysiologic and molecular characteristics of cardiomyocytes after heavy ion irradiation in the frame of the ESA IBER-10 program

Since essentially no information is available on the effects of high linear energy transfer (LET) radiation on the heart, an assessment of possible late effects on the cardiovascular system is important with respect to the planning of manned long-term space missions [ 1, 2]. In order to examine if and to what extent heart muscle cells are affected by an exposure to heavy ions, primary avian cardiomyocytes were isolated, cultured in vitro and exposed at GSI (Darmstadt) to different ion species (carbon, titanium and nickel). Investigation of electrophysiologic radiation effects was performed on cells grown on a microelectrode array (MEA) allowing the monitoring of beat rate, spike shape, field action potential duration and signal conduction pathways across the electrode array. Data were analysed using the DrCell software [ 3]. In parallel, immunohistological stainings were conducted to examine cell cycle progression, DNA-damage repair and apoptosis. Our preliminary data indicate that primary cardiac cells possess a high robustness toward ionizing radiation as cultures receiving doses of up to 7 Gy still show unaltered electrophysiologic activity. This is exemplarily shown in Fig. 1, where the beat rate of cells irradiated with 2 and 7 Gy carbon ions has been plotted. Figure 1 also illustrates that within each treatment group, inter-sample variations are quite large and thus do not allow detection of subtle changes in cellular electrophysiology, probably due to the embryonic character of the cells. Interestingly, in terms of the formation of double-strand breaks (DSBs) and cell cycle progression delay, the cultures showed a dose-dependent reduction in proliferation and DSB accumulation. Taken together, our electrophysiologic studies indicate that the large variations within the same treatment group of avian embryonic cardiomyocytes obscure the detection of radiation effects. To account for this problem, we will use in further studies human cardiomyocytes differentiated from iPS cells, as these cells resemble more closely the condition of an adult human heart and do not undergo developmental changes as embryonic cell cultures do

Symptom Burden and Factors Associated with Acute Respiratory Infections in the First Two Years of Life-Results from the LoewenKIDS Cohort.

Acute respiratory infections (ARIs) are the most common childhood illnesses worldwide whereby the reported frequency varies widely, often depending on type of assessment. Symptom diaries are a powerful tool to counteract possible under-reporting, particularly of milder infections, and thus offer the possibility to assess the full burden of ARIs. The following analyses are based on symptom diaries from participants of the German birth cohort study LoewenKIDS. Primary analyses included frequencies of ARIs and specific symptoms. Factors, which might be associated with an increased number of ARIs, were identified using the Poisson regression. A subsample of two hundred eighty-eight participants were included. On average, 13.7 ARIs (SD: 5.2 median: 14.0 IQR: 10-17) were reported in the first two years of life with an average duration of 11 days per episode (SD: 5.8, median: 9.7, IQR: 7-14). The median age for the first ARI episode was 91 days (IQR: 57-128, mean: 107, SD: 84.5). Childcare attendance and having siblings were associated with an increased frequency of ARIs, while exclusive breastfeeding for the first three months was associated with less ARIs, compared to exclusive breastfeeding for a longer period. This study provides detailed insight into the symptom burden of ARIs in German infants

Cohort Profile: The LoewenKIDS Study - life-course perspective on infections, the microbiome and the development of the immune system in early childhood.

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